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From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: x86@kernel.org
Cc: David Kaplan <david.kaplan@amd.com>,
	linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@kernel.org>
Subject: [PATCH 1/2] x86/spectre_v2: Fix mitigation default on Intel
Date: Tue, 20 May 2025 22:35:20 -0700	[thread overview]
Message-ID: <20250520-eibrs-fix-v1-1-91bacd35ed09@linux.intel.com> (raw)
In-Reply-To: <20250520-eibrs-fix-v1-0-91bacd35ed09@linux.intel.com>

commit 480e803dacf8 ("x86/bugs: Restructure spectre_v2 mitigation")
inadvertently changed the spectre-v2 mitigation default from eIBRS to IBRS
on Intel. While splitting the spectre_v2 mitigation in select/update/apply
functions, eIBRS and IBRS selection logic was separated in select and
update.

This caused IBRS selection to not consider that eIBRS mitigation is already
selected, fix it.

Fixes: commit 480e803dacf8 ("x86/bugs: Restructure spectre_v2 mitigation")
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
 arch/x86/kernel/cpu/bugs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 3d5796d25f786837df59f9ce6358bc875cabe731..7f94e6a5497d9a2d312a76095e48d6b364565777 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2105,7 +2105,8 @@ static void __init spectre_v2_select_mitigation(void)
 
 static void __init spectre_v2_update_mitigation(void)
 {
-	if (spectre_v2_cmd == SPECTRE_V2_CMD_AUTO) {
+	if (spectre_v2_cmd == SPECTRE_V2_CMD_AUTO &&
+	    !spectre_v2_in_eibrs_mode(spectre_v2_enabled)) {
 		if (IS_ENABLED(CONFIG_MITIGATION_IBRS_ENTRY) &&
 		    boot_cpu_has_bug(X86_BUG_RETBLEED) &&
 		    retbleed_mitigation != RETBLEED_MITIGATION_NONE &&

-- 
2.34.1



  reply	other threads:[~2025-05-21  5:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-21  5:35 [PATCH 0/2] eIBRS fixes Pawan Gupta
2025-05-21  5:35 ` Pawan Gupta [this message]
2025-05-21 10:03   ` [tip: x86/core] x86/bugs: Fix spectre_v2 mitigation default on Intel tip-bot2 for Pawan Gupta
2025-05-21  5:35 ` [PATCH 2/2] x86/its: Allow "=stuff" mitigation when eIBRS is enabled Pawan Gupta
2025-05-21  9:59   ` Borislav Petkov
2025-05-21 16:44     ` Pawan Gupta

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